linux下的xargs的簡述
xargs是給命令傳遞引數的一個過濾器,也是組合多個命令的一個工具。它把一個數據流分割為一些足夠小的塊,以方便過濾器和命令進行處理。通常情況下,xargs從管道或者stdin中讀取資料,但是它也能夠從檔案的輸出中讀取資料。xargs的預設命令是echo,這意味著通過管道傳遞給xargs的輸入將會包含換行和空白,不過通過xargs的處理,換行和空白將被空格取代。
xargs 是一個強有力的命令,它能夠捕獲一個命令的輸出,然後傳遞給另外一個命令,下面是一些如何有效使用xargs 的實用例子。
1. 當你嘗試用rm 刪除太多的檔案,你可能得到一個錯誤資訊:/bin/rm Argument list too long. 用xargs 去避免這個問題
find ~ -name ‘*.log’ -print0 | xargs -0 rm -f
2. 獲得/etc/ 下所有*.conf 結尾的檔案列表,有幾種不同的方法能得到相同的結果,下面的例子僅僅是示範怎麼實用xargs ,在這個例子中實用 xargs將find 命令的輸出傳遞給ls -l
# find /etc -name "*.conf" | xargs ls –l
3. 假如你有一個檔案包含了很多你希望下載的URL, 你能夠使用xargs 下載所有連結
# cat url-list.txt | xargs wget –c
4. 查詢所有的jpg 檔案,並且壓縮它
# find / -name *.jpg -type f -print | xargs tar -cvzf images.tar.gz
5. 拷貝所有的圖片檔案到一個外部的硬碟驅動
# ls *.jpg | xargs -n1 -i cp {} /external-hard-drive/directory
EXAMPLES
find /tmp -name core -type f -print | xargs /bin/rm -f
Find files named core in or below the directory /tmp and delete them. Note that this will work incorrectly if there are any filenames containing newlines or spaces.
find /tmp -name core -type f -print0 | xargs -0 /bin/rm -f
Find files named core in or below the directory /tmp and delete them, processing filenames in such a way that file or directory names containing spaces or newlines are correctly handled.
find /tmp -depth -name core -type f -delete
Find files named core in or below the directory /tmp and delete them, but more efficiently than in the previous example (because we avoid the need to use fork(2) and exec(2) to launch rm and we don't need the extra xargs process).
cut -d: -f1 < /etc/passwd | sort | xargs echo
Generates a compact listing of all the users on the system.
xargs sh -c 'emacs "[email protected]" < /dev/tty' emacs
Launches the minimum number of copies of Emacs needed, one after the other, to edit the files listed on xargs' standard input. This example achieves the same effect as BSD's -o option, but in a more flexible and portable way.
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作者:陽光島主
來源:CSDN
原文:https://blog.csdn.net/ithomer/article/details/7303501
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